code: def if_example_data(f):
      return if_datasource(example_data, "Cannot find example data")(f)
  
file_path: nipy/nipy/testing/decorators.py
imports: import functools
  from unittest import skipIf
  from nibabel.optpkg import optional_package
  from nipy.utils import DataError, example_data, templates
label_desc: Use image node_id 5 for calling a global function with example usage: if_example_data(f) and returns: if_datasource